Objective
The objective was to estimate the prevalence of both dementia and depression among community-dwelling older Americans and to determine if hospitalization is independently associated with dementia or depression in this population.

Method
This cross-sectional study utilized data from a nationally representative, population-based sample of 7197 community-dwelling adults ≥ 65 years old interviewed in 2011 as part of the National Health and Aging Trends Study. Information on hospitalizations was obtained from self- or proxy-report. Possible and probable dementia was assessed according to a validated algorithm. Depressive symptoms were assessed with the Patient Health Questionnaire-2.

Results
An estimated 3.1 million community-dwelling older Americans may have dementia, and approximately 5.3 million may have substantial depressive symptoms. After adjusting for demographic and social characteristics, medical diagnoses, smoking history, serious falls and pain symptoms, being hospitalized in the previous year was independently associated with greater odds of probable dementia (odds ratio [OR]: 1.42, 95% confidence interval [95% CI]: 1.16–1.73) and substantial depressive symptoms (OR: 1.60, 95% CI: 1.29–1.99).

Conclusions
Dementia and depression are common in community-dwelling older Americans, and hospitalization is associated with these conditions. Additional research increasing understanding of the bidirectional relationship between hospitalizations, dementia and depression, along with targeted interventions to reduce hospitalizations, is needed.